Method of mulling

ABSTRACT

Method of mulling material in which the material is continuously delivered to and discharged from a receptacle. The material is dispersed in the receptacle and is distributed on the inner cylindrical mulling surface of the receptacle to be mulled on the mulling surface as the material continuously flows through the receptacle.

United States Patent Inventor Karl l-l. Andree [56] References CitedColumbus, Ohio UNITED STATES PATENTS P 469,145 2/1892 Hughes 241 /130x 1rs N 33 936 D 27 1963 507,432 10/1893 Griffin..... 241/129x g' gygu gg 31 1 1,706,417 3/1929 Simpson.. 241/124x Patented Mat 2 2,575,410 11/1951Davis 241/98X Assignee Jeffrey Galion Manufacturing Company Emmme'DnaldKelly Att0rneyDavid Young METHOD OF MULLING 5 Claims, 11 Drawing Figs.

US. Cl 241/ 17, ABSTRACT: Method of mulling material in which themateri- 241/29 al is continuously delivered to and discharged from areceptalnt.Cl ..B02c 15/08, cle. The material is dispersed in thereceptacle and is dis- B02c 21/00 tributed on the inner cylindricalmulling surface of the recep- Field of Search 241/15- tacle to be mulledon the mulling surface as the material con- 18, 22, 29, 30, 42, 43, 98,124, 129, 130 tinuously flows through the receptacle.

I 1 l I 37 i 34 F 1' E f, i U

i i i Q1 I l I i ,1L 31 I J 2 i) 7 i E I I F 24 e 1 i i 23 1 1 u 1PATENTEDHAR 2M1 3567;139

SHEET 1 BF 4 INVENTOR, KARL HAN DRAE,

HTT'Y METHOD OF MULLING This application is a division of applicationSer. No. 333,936, filed Dec. 27, 1963, Pat. No. 3,430,874, issued Mar.4, I969.

The instant invention relates to the mulling of materials, for exampleas is practiced in foundry operation in respect to the preparation ofsand for making molds, and more particularly, to an improved method ofmulling.

This invention has application to the treatment of materials by mulling,for example, the mulling of sand in a foundry to place the same insuitable condition for use in making molds in metal casting operations.The mulling of the sand may involve new sand which has not previouslybeen used in making molds, recirculated sand which has been used inmolds and is circulated in the foundry system for reuse, or acombination of the two. In any of these cases it is required that thesand be mulled, which involves adding to the sand and combiningtherewith certain ingredients, particularly water and bonding agents. Inthe mulling operation, it is desired that these ingredients be uniformlycombined with the mass of sand, and in an ideal operation each grain ofsand is completely and uniformly coated with the added ingredients,whereby the mass of sand discharged from the mulling operation has thenecessary bonding characteristics, such that it may be formed into moldsinto which hot molten metal may be poured.

The mulling of the sand is essentially a pressing, kneading and mixingoperation in which the sand and the added ingredients are constantlybeing pressed, kneaded and mixed until the added ingredients areuniformly dispersed in the mass of sand, and the grains of sand are eachcoated with the bond- 2 ing materials. In mulling operations, in whichrecirculated sand is being operated upon, such sand is usually very hotas the result of being in contact with hot molten metal, and is farhotter than is desired for the mulling operation or for the formation ofmolds. In such case it 'is necessary that the sand be cooled, and thismay be accomplished during the mulling operation by circulating airthrough the sand, in addition to the tempering water that is added. Alsoin connection with the preparation of the sand for the making of molds,it is desired that the sand be aerated, which consists essentially ofbreaking up any lumps in the sand and placing the massof sand in aloose, uniform condition, in which it may be readily and uniformlypacked around a pattern in the process of making a mold with such sand.l

It is an object of the instant invention to provide an improvedcontinuous method for the preparation of materials by mulling, forexample, sand to be used in the making of molds.

It is. a further object of the instant invention to provide an improvedmethod of continuously mulling materials, in which the material isdispersed around an axis and distributed over a cylindrical mullingsurface as the material continuously flows in a longitudinal direction.

Other objects of the invention will appear hereinafter, the novelfeatures and combinations being set forth in the appended claims.

' In the drawings:

FIG. 1 is an elevational view of an exemplary installation ofthecontinuous muller of the instant invention;

FIG. 2 is an elevational view of the continuous muller installationlooking towards the feed or upstream end of the continuous muller;

FIG. 3 is a plan view of the continuous muller installation;

FIG. 4 is an elevational view, partially in section, of the dischargeend of the continuous muller; FIG. 5 is a longitudinal, elevational viewof the continuous muller, partially in section;

FIG. 6 is a transverse sectional view of the continuous muller, taken onthe line 6-6 in FIG. 5;

FIG. 7 is a partial transverse sectional view of the continuous muller,showing a typical mulling assembly, taken on the line 7-7 in FIG. 5;

FIG. 8 is an elevational view of a typical mulling assembly, viewed fromthe line 8-8 in FIG. 7;

FIG. 9 is a sectional view of a typical mulling assembly, taken on theline 9-9 in FIG. 7;

FIG. 10 is an elevational view of the intake accelerating plow, viewedfrom the line 10-10 in FIG. 6; and

FIG. 11 is an elevational view of the sweeper blade, viewed from theline 11-11 in FIG. 5.

Referring to the drawings, and particularly FIGS. 1, 2 and 3, there isillustrated therein an exemplary installation of a continuous muller 20that is constructed in-accordance with this invention. The mullerinstallation illustrated herein is such as would be appropriate in afoundry, and the material treated in such muller installation is foundrysand to be used in the making of molds. In such installation thecontinuous muller 20 is mounted on a supporting base 21, which may befabricated from steel plate and structural iron members. The supportingbase 21 has a raised platform 22 at one end, on which there are secureda motor 23 and a reducer 24. The motor 23 is connected to the reducer 24by a suitable torque coupling 25, and the reducer is connected to thecontinuous muller by a suitable drive coupling 26. The continuous muller20 is so constructed that the drive may be applied to either endthereof.

A feed chute 27 is secured to one end of the continuous muller 20, thisbeing the feed end or upstream end of the apparatus. The feed chute 27is constructed in the manner of a hopper, and the material deliveredinto the feed chute 27 flows therefrom into the continuous muller 20. Abelt conveyor 28 is placed with its head pulley 29 above the feed chute27, in position to discharge material from the belt conveyor 28 into thefeed chute 27. The sand which is to be treated in the continuous muller20, is delivered thereto by the belt conveyor 28. Preferably, the beltconveyor 28 is enclosed in a housing 30 to reduce the incidence of dustfrom the sand that is carried by the belt conveyor 28. The housing 30has an open end which overlies the top of feed chute 27 and throughwhich material discharges into the feed chute 27. The housing 30 issecured to the top of the feed chute 27 by a plurality of bolts, or likesecuring means, passed through like flanges 31 formed on the feed chute27 and housing 30.

Above the conveyor housing 30 there is mounted a screw feeder 32 havinga hopper 33, in which there is placed a quantity of bonding material orother ingredient to be added to the sand and to be combined therewith inthe mulling operation.

The screw feeder 32 includes a cylindrical feeding conduit through whichthere extends a screw 35. The bonding material stored in the hopper 33is fed therefrom by the screw 35 to the open end of the cylindrical feedconduit 34, whence the bonding material discharges through an opening 36formed in the top of the conveyor housing 30 onto the belt conveyor 28.The rate of delivery of the bonding material by the screw feeder 32 maybe controlled by suitable means governing the speed of operation of thescrew feeder 32, which ultimately controls the proportion of bondingmaterial added to the sand that is being delivered to the continuousmuller 20. Only one screw feeder 32 is shown in the drawings forillustrative purposes. It will be understood, however, that more thanone screw feeder 32 may be utilized; for example where it is desired toadd more than one ingredient to the sand, one screw feeder 32 may beutilized for each ingredient to be added to the sand.

Within the conveyor housing 30 there is a transversely extending pipe37, which has a plurality of downwardly directed perforations along itslength overlying the belt conveyor 28. The pipe 37 is connected to asource of water, and the water discharges from the pipe perforations todeliver tempering water to the sand as it is fed to the continuousmuller 20 by the belt conveyor 28. A suitable valve is preferablyincluded in the pipeline for regulating the amount of tempering waterdelivered to the sand by the pipe 37.

The sand that is delivered to the continuous muller 20 flows through theapparatus in a stream away from the feed or upstream end of thecontinuous muller 20 and towards the discharge or downstream endthereof. As the sand flows downstream through the continuous muller 20,it is mulled within the apparatus and finally discharges from thecontinuous muller 20 at the discharge or downstream end thereof, at

which there is provided a discharge chute 38 for the discharging sand.In the exemplary continuous muller installation illustrated herein, abelt conveyor 39 is disposed below the discharge chute 38 tocontinuously receive and remove the mulled sand as it is discharged.

The exemplary continuous muller installation as described thus far, iscustomarily included in a complete foundry system. The belt conveyor 28would have its tail end disposed at a position in the foundry to receivethe sand that is shaken out of the molds. Such sand is then moved by thebelt conveyor 28 to the continuous muller 20. It will be understood thatnew sand may also be delivered to the belt conveyor 28 for mulling suchsand, either combined with the sand that has been previously used, or asnew sand alone.

The belt conveyor 39 may extend from the continuous muller to a positionin the foundry at which the mulled sand is delivered to suitable storagehoppers at molding stations, from which such sand may be taken as neededfor the making of molds. Of course, the continuous muller 20 may beutilized in other arrangements or installations than that illustratedherein, such illustration being merely by way of example.

The continuous muller installation may additionally include means forcausing a current of air to flow through the continuous muller 20 forthe purpose of cooling the sand, and additionally, for the removal ofsteam from the interior of the muller 20. The sand becomes quite hotafter it has been used in a mold, by reason of its contact with the hotmetal therein. It is desired that the sand be cooled appreciably duringthe mulling operation and prior to being reused in the molds. Suchcooling may be accomplished in part by the addition of excess temperingwater by the water pipe 37. Such excess water evaporates out of the hotsand, forming steam in the continuous muller 20. The stream may be drawnoff from the continuous muller 20 by a current of air flowing throughthe same. At the same time, the passage of a current of cool air throughthe continuous muller 20 will provide some additional cooling of thesand therein.

For the purpose of causing the current of air to flow through thecontinuous muller 20, there is provided an air duct 40 connected to thefeed or upstream end of the continuous muller. A suitable exhaust fanmay be connected to the air duct 40 to draw cool air through thecontinuous muller 20, the air intake in this case being the dischargechute 38. In such arrangement the current of air flows from thedischarge or downstream end to the feed or upstream end of thecontinuous muller 20, or

- stated another way, there is a countercurrent flow of air. Al-

ternatively, the current of air may flow through the continuous muller20 in a concurrent direction, that is from the feed or upstream end tothe discharge or downstream end of the continuous muller 20. In eitherthe countercurrent or concurrent flow of air through the continuousmuller 20, the air may be caused to flow through the continuous muller20 either by being blown through the continuous muller 20 by a suitableblower, or exhausted from the continuous muller 20 by a suitable exhaustfan.

The continuous muller 20 comprises a cylindrical, drumlike receptacle 45placed on a substantially horizontal axis, whereby the cylindricalreceptacle 45 is disposed in a lateral position extending along itsaxis. The receptacle 45 is supported on feet 46,47 which may be formedof steel plate that is shaped to the desired configuration and securedto the receptacle 45 in a suitable manner, as by welding. The feet 46,47are placed at opposite ends of the receptacle 45 for securing thecontinuous muller 20 to the supporting base 21, as by a plurality ofbolts.

The receptacle 45 includes a cylindrical shell 48. The feed or upstreamend of the cylindrical shell 48 is closed by an end wall 49, and thedischarge or downstream end of the cylindrical shell 48 is closed by asimilar end wall 50. Each of the end walls 49,50 is formed of a platehaving a disclike form. The cylindrical shell 48 and the end walls 49,50are preferably formed of steel plate, or the like, with the end walls49,50 being received within the ends of the cylindrical shell 48, and

being secured thereto, as by welding, whereby the receptacle 45 is arigid, structural subassembly of the continuous muller 20. For thepurpose of further rigidifying the receptacle 45, a plurality oflongitudinally extending ribs 51 are secured to the outer wall of thecylindrical shell 48, as by welding. The ribs 51 preferably areradiallyv disposed on the cylindrical shell 48. At the top of thecylindrical shell 48 there are secured two apertured cars 52, one ateach end thereof, in which crane hooks may be received for raising andlowering the continuous muller 20 .when it is necessary to move thesame.

The receptacle 45 is provided with an opening that extends the fulllength thereof in an upper quadrant of the cylindrical shell 48, as bestseen in FIGS. 4 to 6. The opening is illustrated as being of lesserarcuate length than however, it will be understood that the size of theopening is governed by the need for reaching inside the receptacle 45for maintenance of the various elements of the continuous muller 20 thatare contained therein. The opening is closed by a cover 55, which formsa continuation of the cylindrical shell 48, and in effect, comprises thecylindrical shell 48 when the cover 55 is in its closed position, asseen in FIGS. 4 to 6.

The cover 55 is connected to the receptacle 45 at each end thereof by ahinge 56 having a longitudinally extending axis, whereby the cover 55may be readily raised to its open position 57, as shown in phantom linesin FIG. 4. To facilitate raising the cover 55, there may be provided apneumatic cylinder 58 with its cylinder end pivotally secured to the endwall 50 on a bracket 59, with a pin 60 by which the pival connection ofthe cylinder 58 to the bracket 59 is effected. The piston rod 61 of thecylinder 58 has a clevis 62 at its upper end by which it is connected toa depending ear 63 with a pivot pin 64. The ear 63 is secured to thecover 55, and the pin 64 forms a pivotal connection between the pistonrod 61 and the cover 55. A control valve 65 is secured to the end wall50 and is connected to the pneumatic cylinder 58 for operating it toraise and lower the cover 55 as desired.

The cover 55 has a tail plate 66 which is secured thereto at one sideand extends from approximately the upper edge of the cover 55 in acircular arc having its center on the axis of hinge 56. The tail plate66 is a planar element disposed adjacent to the end wall 50. At the endof the tail plate 66 there is secured a rectilinear guide 67 withinwhich there is slidably supported a bolt 68. Below the tail plate 66there is provided an arcuate track 69 which is concentric with the tailplate 66. When the cover 55 is moved to its open position'57, the bolt68 moves along the track 69, in contact with the top of the same, untilthe cover 55 has reached its fully opened position, at which therectilinear guide 67 is beyond the end of the track 69 and the bolt 68drops down past the end of the track 69. The arcuate length and positionof the track 69 are determined in accordance with the length of the arcthrough which the cover 55 is swung to raise it to its fully openedposition, so that when the cover 55 is at its fully opened position, thebolt 68 drops past the end of the track 69.-The bolt 68 and the track 69together provide a positive stop which prevents the cover 55 from beinginadvertently lowered or accidentally falling, and constitutes a safetydevice which is desirable by reason of the weight of the cover 55.

The bolt 68 has a pin 70 extending through a slot 71 in the rectilinearguide 67. By means of the pin 70, the bolt 68 may be withdrawn into therectilinear guide 67, and the cover 55 then lowered by reverse operationof the pneumatic cylinder 58. Once the bolt 68 has passed rearwardlybeyond the end of the track 69, and into engagement with the top of thetrack 69, it is maintained in withdrawn position by the track 69.

At the lower edge of the receptacle opening there is a longitudinallyextending locking bar 74 which projects outwardly from the cylindricalshell 48. The lower edge of the cover 55 has a like, longitudinallyextending locking bar 75 which is secured thereto and is disposed to bein parallel position to the locking bar 74 when the cover 55 is in itsclosed position. The cover 55 is locked by special locking bolts 76,several of which are disposed along the locking bars 74,75 to secure thelocking bars 74,75 to each other. Each locking bolt 76 includes a boss77 which is disposed between a pair of upright ears 78, the latter beingsecured to the upper surface of the locking bar 75. A pivot pin 79extends through the boss 77 and the ears 78 to provide a pivotalconnection of the boss 77 and the bolt 76 to the cover locking bar 75.The locking bars 74,7 5 are formed with lateral slots 80,81respectively, which are aligned with the bolts 76 so that the bolts 76may be swung about their pivot pins 79 and through the slots 80,81. Anut 82 is threaded on the bolt 76 and a washer 83, or the like, issecured to the end of the bolt 76 to form a retaining flange to preventthe nut 82 from being removed from the bolt 76.

Normally, the bolt 76 is disposed in depending position, as seen in FIG.6, and. extends through the locking bars 74,75. The nut 82 is turned upon the bolt 76 against the underside of the locking bar 74, therebylocking the cover 55 in closed position. When it is desired to open thecover 55, a first step is to turn each of the nuts 82 down on the bolts76 and to swing the bolts 76 upwardly about their respective pivot pins79 to the position shown in phantom lines in FIG. 4. This releases thecover locking bar 76 from the lower locking bar 74 and permits the cover55 to be raised as previously described.

Referring now to FIG. 5, there is a shaft 85 that extends throughthereceptacle 45, with its axis coincident with the axis of thecylindrical shell 48. .The opposite ends of the shaft 85 are rotatably.supported on the end walls 49,50. The means for rotatably supporting theopposite ends of the shaft 85 are the same, and accordingly, suchsupporting means will be described only with respect to the end of theshaft 85 at the feed or upstream end of the receptacle 45, it beingunderstood that the description applies to the like supporting means atthe discharge or downstream end of the receptacle 45 for the other endof the shaft 85.

The end wall 49 has a centrally disposed circular opening 86 which isconsiderably larger than the diameter of the shaft 85, and the shaft 85extends through such opening 86. Within the opening 86, at the outerside of the end wall 49, there are placed the two halves of a disclikeretainer 87, the latter having a central aperture through which theshaft 85 passes. The opening 86 is filled with a felt packing seal 88that is placed adjacent to the disc 87. The felt seal 88 fills theopening 86 and forms a seal against the periphery of the shaft 85. Thefelt seal 88 is held in the opening 86, at the inside of the wall 49, bya pair of rectangular retainer plates 89,90, as seen in FIG. 6. Theplates 89,90 are secured to the end wall 49 by a plurality of bolts 91.The rectangular plates 89,90.have semicircular cutouts, so that whenplaced side by side as shown, there is formed a circular opening throughwhich the shaft 85 passes. Upon securing the plates 89,90 to the endwall 49, the packing 88 is compressed in the end wall opening 86 betweenthe retainer 87 and the plates 89,90, whereby the packing 88 fills theopening 86 and seals the shaft 85 therein.

The shaft 85 projects beyond the end wall 49 and is formed with areduced diameter end 92 that is received in a flange roller bearing 93to be rotatably supported thereby. A ring 94 is disposed between theflange bearing 93 and the end wall 49. The ring 94 is secured to the endwall 49, as by welding. The internal diameter of the ring 94 is smallerthan the diameter of the opening 86, whereby the ring 94 forms ashoulder to back the retainer 87 and to secure the latter in the opening86. The flange roller bearing 93 is secured to the ring 94 and the endwall 49 by a plurality of bolts 95, or the like, as seen in FIG. 4. Thering 94 is partially cut away to provide an opening 96 at the bottomthereof, which is of substantial size. Any material which might get pastthe felt seal 88 will drop to the bottom of the ring 94 and out throughthe opening 96, and thereby such material is prevented from working itsway into the flange roller bearing 93. A shaft guard 97 is secured tothe end wall 49 below the ring 94 and extends upwardly therefrom to theexposed end of the reduced diameter shaft end 92. The shaft guard 97 hasa cup 98 which covers the shaft end 92'. The shaft guard 97 is bolted toa channel support 99, which is secured to the end wall 49, as bywelding. The shaft guard 97 is installed on that end of the continuousmuller 20 that is the nondriven end.

The end wall 49 has a feed opening 100 disposed at one side of the shaft85, and at the opposite side thereof there is a rectangular opening 101for the supply or exhaust of a current of air that may flow through themuller receptacle 45 as previously described. The feed chute 27terminates at its bottom in an opening that is aligned with and connectsto the feed opening 100 for the discharge of sand into the mullerreceptacle 45. The air duct 40 connects to the rectangular opening 101for the flow of air through the continuous muller, as above described.

The sand is received in the muller receptacle 45 at the feed or upstreamend and then flows in a downstream direction through the receptacle 45to the downstream or discharge end thereof, at which there is adischarge section 102 from which the sand discharges through thedischarge chute 38. As the sand flows through the receptacle 45, it issuccessively mulled by a plurality of successive mulling assemblies105a, 105b, 105 c, 105d, 105e, l05f, 105g, 105k, all of which areidentical, except for the mulling assembly 1050 which has an additionalelement, as will be described hereinafter. In the interest of clarity,FIG. 5 includes a complete illustration of only the mulling assemblies105a, 105b, which are the first and second mulling assemblies in thedirection of flow from upstream to downstream. The remainingmullingassemblies 105c-h are merely represented by an outline of themulling wheels and plows thereof. The description of the mullingassemblies 105a, 105k is applicable to the mulling assemblies 105ch,except as to the one added element of the mulling assembly 105a, as willbe specifically mentioned hereinafter.

The several mulling assemblies 105ah are secured to the shaft to bemoved thereby about the axis of the shaft 85. The mulling assembliesl05ah are disposed at equally spaced positions along the shaft 85between the feed or upstream end of the mulling receptacle 45 and thedischarge section 102. Thus, as the sand flows through the mullerreceptacle 45 from the feed or upstream end thereof towards thedischarge section 102 at the discharge or downstream end of the mullerreceptacle 45, the mulling assemblies 105a-h successively operate on andmull the sand. The successive positions ofthe several mulling assembliesl05a-h along the shaft 85 are apparent in FIG. 5, and are furtherindicated by the letters a-h at the bottom of FIG. 5, identifying andlocating the several successive mulling positions along the length ofthe mulling receptacle 45.

For each mulling assembly 105a-h there is secured to the shaft 85 apartial hub 106, as best seen in FIGS. 5 to 8. The hub 106, asillustrated herein, extends through an angle somewhat greater than 180,sufficient to receive three bolts at positions spaced relatively to eachother. Each partial hub 106 is firmly secured to the shaft 85, as bywelding, for

mounting a mulling assembly 105.

Referring to FIG. 7, there is illustrated therein the mulling assemblyb, which is typical of the construction of the several mullingassemblies l05ah. The mulling assembly 105b is constructed on a frame107. The frame 107 comprises a center hub portion 108 formed with anarcuate recess 109 that is open along a diametral line, whereby theframe 107 and the mulling assembly 105b may be placed over the shaft 85.The recess 109 is formed on a circular are having a radius equal to theradius of the shaft 85. Thus, the frame 107 may be seated on the shaft85. The hub portion 108 of the frame I07, and the partial hub 106, areeach formed with three apertures which may be at 90 spaced positionsrelative to each other about the axis of the shaft 85. The apertures inthe partial hub 106 and in the center hub portion 108 of the frame 107are aligned with each other to receive three bolts 110, by which theframe 107 is securedlo the partial hub I06 and is mounted on the shaft85. In effect then, the entire 'mulling assembly 105b is secured to theshaft 85 by the several bolts 110. By releasing the bolts 110, theentire mulling assembly 105b may be removed from the shaft 85 forreplacement, repair or other maintenance of the same as may be required.

The frame 107 further includes a first mounting arm 111 and a secondmounting arm 112. The mounting arms 111,112 are formed as extensions ofthe frame hub portion 108, and extend from opposite sides of the hubportion 108. The outer end of the first mounting arm 111 is formed withan integral sleeve 113. Within the sleeve 113 there are provided a pairof torsion bushings 114, which are press fitted in the bore of thesleeve 113, as seen in FIG. 9. Each torsion bushing 114 comprises ametal sleeve 115, on the outer surface of which there is bonded acylinder 116 of rubber, or like yieldable material. The bond between themetal sleeve 115 and the outer rubber cylinder 116 causes the latter tobe immovable relatively to the metal sleeve 115 at the metal-rubberjunction. However, the rubber cylinder 116 is yieldable to an increasingextent as the radial distance of the rubber cylinder 116 increases fromthe junction of the rubber to the metal. It is this yieldablecharacteristic of the torsion bushing 114 that is utilized in themulling assembly 10511.

The two torsion bushings 114 are press fitted in the bore of the sleeve113, whereby the rubber cylinders 116 are compressed, setting up a forcepressing the rubber against the bore of the sleeve 113, as well asagainst the metal sleeve 115 of the torsion bushing 114. Such pressure,in effect, immovably secures the peripheral surfaces of the rubbercylinders 116 to the bore of the sleeve 113. Then, if there is atorsional force applied to the metal sleeve 115, such force is resistedby the rubber cylinders 116 which tend to maintain themselves in aneutral position in which they are not distorted. If the torsional forceexceeds the spring rate of the rubber cylinders 116, then there isrelative rotation of the metal sleeves 115 and the sleeve 113.

A hub 117 is formed with an integral shaft 118 that is received in thebores of the torsion bushings 114, and has a threaded end that projectsbeyond the torsion bushings 114. The hub 117 bears against an end metalsleeve 115 of the torsion bushings 114 that projects beyond the sleeve113, whereby the hub 117 is spaced from the one end of the sleeve 113. Awasher 119 is mounted on the projecting end of the shaft 118 and bearsagainst an end ofa metal sleeve 115 of the torsion bushings 114 thatprojects beyond the other end of the sleeve 113, to space the washer 119from the other end of the sleeve 113. A nut 120 is turned on thethreaded end of the shaft 118, whereby the hub 117 is pressed againstone end ofa metal sleeve 115 of the torsion bushings 114, and the washer119 is pressed against another end ofa metal sleeve 115 of the torsionbushings 114. In effect then, the hub 117 is fixedly secured to themetal sleeve 115 of the torsion bushings 114. There is nocontact betweenthe hub 117 and the rubber cylinders 116 of the torsion bushings 114 byreason of the conical configuration of each end of the rubber cylinders116.

The torsion bushings 114 are interposed between the mounting hub 117 andthe sleeve 113 of the frame 107. Thus, the hub 117 can rotate or pivotabout the axis of its shaft 118 and relatively to the sleeve 113.However, the interposition of the torsion bushings 114 provides ayieldable means which resists such rotation or pivotal movement of thehub 117, to the extent of the spring rate of the rubber cylinders 116 ofthe torsion bushings 114.

A centrally disposed boss 121 projects from the outer side of the hub117. A supporting lever 122 is formed with an aperture 123 in which theboss 121 is received when the supporting lever 122 is mounted on the hub117. The supporting lever 122 is fixedly secured to the hub 117 by aplurality of bolts 124, of which there may be three.

The supporting lever 122 has the form of a crank and comprises an outerarm 125 and an inner arm 126. At the end of the outer arm 125 there isformed an integral axle 127, the axis of which is parallel to the axisof the shaft 85. A first bearing 128 is mounted at the inner end of theaxle 127 abutting an annular shoulder 129. A second bearing 130 ismounted on the axle 127 at the outer end thereof, with a spacer 131disposed between the bearings 128, 130 to maintain them in spaced-apartpositions. The axle 127 has a threaded end 132 on which there is turneda nut 133 which secures the bearings 128, 130 on the axle 127.

A mulling wheel 135 is rotatably mounted on the axle 127, with thebearings 128,130 interposed between the mulling wheel hub 136 and theaxle 127. The bore 137 of the mulling wheel hub 136 is formed with ashoulder 138 at the inner end thereof against which the bearing 128 isseated. in the outer end of the bore 137 there is placed a spacer 139which abuts the second bearing 130. The axle 127 terminates short of theend of the bore 137. A cover 140 overlies the outer end of the bore 137and is secured to the hub 136 by a plurality of bolts 141. An O-ring 142is interposed between the cover 140 and the hub 136 to assure a sealtherebetween. The cover 140 thus closes the outer end of the bore 137and prevents material from getting into the bore 137 and contaminatingthe bearings 128,130. The cover 140 also secures the spacer 139 inposition against the second bearing 130 and thereby fixes the positionof the mulling wheel 135 on the axle 127.

It is necessary that the inner end of the bore 137 also be sealed toprevent material from reaching the bearings 128,130 and contaminatingthese. Accordingly, at the inner end of the bore 137 there is formed anoutwardly facing annular seat 143. The outer arm 125 is also formed withan annular seat 144 which is aligned with and oppositely disposed withrespect to the first annular seat 143. Between the annular seats 143,144there is placed a rotating seal 145. Such rotating seal 145 comprises apair of like, oppositely disposed metal rings 146,147 that have abuttingsurfaces. The abutting surfaces of the metal rings 146,147 have asuperfine finish, such that the rings 146,147 are rotatable relativelyto each other, but by abutment of their superfine finished surfacesthere is maintained such an intimate contact of the rings 146,147 witheach other that there is effected a seal between the relatively rotatingrings 146,147. An elastic ring 148 is disposed between the first annularseat 143 and the metal ring 146, and a similar, oppositely disposedelastic ring 149 is disposed between the other annular seat 144 and themetal ring 147. The elastic rings 148,149 are press fitted in therespective annular seats 143,144 and extend therefrom in oppositedirections at an angle towards the opposite annular seats on therespective rings 146,147. The angular disposition of the elastic rings148,149 is such as to press the metal rings 146,147 towards each otherto maintain the surfaces thereof in abutting contact. Also, the elasticring 148 maintains the metal ring 146 rotatively fixed relatively to thehub 136, and the elastic ring 149 similarly maintains the metal ring 147rotatively fixed relatively to the outer arm 126, whereby rotation ofthe mulling wheel 135 produces relative rotation of the metal rings146,147 while sealing engagement thereof is maintained by the elasticrings 148,149. The elastic rings 148,149 seal the area between the metalrings 146,147 and the annular seats 143,144, respectively.

The mulling wheel 135 has a tire 153 formed of rubber, or like yieldablematerial. The tire 153 is bonded to a metal band 154, and the tire 153is secured to the hub 136 by press fitting the metal band 154 on the hub136. Thus, the mulling wheel 135 is freely rotatable on the axle 127 bythe bearings 128,130, which are interposed between the hub 136 and theaxle 76 the bore 137 of the hub 136 is sealed at its outer end by thecover 140, and at its inner end by the rotating seal 145, the lattereffecting a seal between the inner end of the bore 137 and the outer arm125. Thus, the bearings 128,130 are protected from the material that isdispersed in the receptacle 45. Were such materials to reach thebearings 128,130, the latter could be damaged and rendered ineffectivein short order. The seals also serve to retain the lubricant for thebearings 128,130 within the bore 137.

The outer arm 125 supports a dam 155, the latter being a planar, platemember that is laterally disposed with respect to the axis ofthe shaft85. The boss 121 has a centrally disposed pin 156 projecting therefrom,and the dam has an aperture 157 of the same size as the pin 156, toreceive the latter. The dam 155 includes a first arcuate slot 158 and asecond arcuate slot 159, through which there extend bolts 160,161,respectively, that are threaded into the outer arm 125 to secure the dam155 on and against the outer arm 125. The

slots 158,159 are spaced at different distances from the axis of the pin156. Thus, there are three points of support for the dam 155, thesebeing the pin 156 and the two bolts 160,161. The slots 158,159 areformed on arcs of concentric circles that have their center on the axisof the pin 156. Thus, the position of the dam 155 can be adjusted aboutthe axis of the pin 156. The outer edge 162 of the dam 155 is formed ona circular are having its center on the axis of the shaft 85. Thus, theouter edge 162 is concentric with the cylindrical wall of the receptacle45. By adjustment of the position of the dam 155, the spacing betweenits outer edge 162 and the wall of the cylindrical receptacle 45 may beadjusted for a purpose that will be more fully explained hereinafter.

The inner arm 126 extends from the boss 123 to a position adjacent theshaft 85. At the end of the inner arm 126 there is secured an eccentricdisc 163 which abuts the shaft 85. A bolt 164 releasably secures theeccentric disc 163 to the inner arm 126, whereby the position of theeccentric disc 163 may be adjusted, thereby varying the spacing betweenthe end of the inner arm 126 and the shaft 85, when the eccentric disc163 is in contact with the shaft 85. The disposition of the outer arm125 is adjusted accordingly, with the ultimate effect of adjusting theoutermost position of the mulling wheel 135 relatively to the wall ofthe cylindrical receptacle 45.

The second mounting arm 112 of the mulling assembly frame 107 has threepairs of apertures 165,166, 167 which are spaced from each other and aredisposed in two circular arcs that are concentric. A plow 170 is mountedon the second mounting arm 112. The plow 178 has an arm 171 with abifurcated end 172 that has a pair of apertures which are spaced apartthe same distance as the individual apertures of each pair of apertures165,166,167. The second mounting arm 112 is received within thebifurcated end 172 of the plow arm 171 and is releasably secured theretoby a pair of bolts 173 extending through the apertures in the bifurcatedend 172 of the plow arm 171 and one pair of the apertures 165,166,167,which is aligned therewith. The plow arm 171 extends towards thecylindrical shell 48 of the receptacle 45 and terminates in an integralfoot 174 that extends laterally to opposite sides of the arm 171. Thefoot 174 has a flat surface facing inwardly of the receptacle shell 48,and this flat surface is inclined with respect to a tangent to thereceptacle shell 48, and is substantially parallel to the axis of theshaft85. A plow blade 175 is releasably secured to the foot 174. Theplow blade 175 includes a pair of bolts 176 disposed one on each side ofthe arm 171 and extending through aligned apertures in the foot 174 toreceive nuts that are turned on the bolts 176 to firmly secure the plowblade 175 to the foot 174. The leading edge of the plow blade 175 isdisposed closely adjacent to the inner surface of the receptacle shell48 and extends therefrom at the same angle of inclination as the foot174.

The inclination of the plow blade 175 may be adjusted by selection ofthe pair of apertures 165,166,167 to which the plow 178 is secured bymeans of the bolts 173. The pairs of apertures 165,166,167 are disposedin concentric circular arcs having a center approximately on the leadingedge of the plow blade 175, whereby in any position of adjustment ofinclination of the plow blade 175 the spacing between the leading edgeof the plow blade 175 and the inner surface of the receptacle shell 48remains substantially the same.

The inner cylindrical surface of the receptacle 45 provides the mullingsurface on which the sand is mulled as it flows through the receptaclein a longitudinal direction. In order to form a suitable mulling surfaceon the receptacle shell 48, there is provided a liner 188 formed ofrubber, or like yieldable material. The liner 188 is formed in threesections, of which two liner sections 181,182 are of equal arcuatelength and are secured to the receptacle shell 48, and the third linersection 183 is of shorter arcuate length and is secured to the cover 55Except for the arcuate length of the several sections 181,182,183 of theliner 180, the construction of these is the same, and accordingly, onlyone liner section need be described in detail.

The liner section 181 comprises a metal backing plate 184 which extendsthe length of the receptacle 45 from one end wall 49 to the other endwall 50. Bonded to the metal plate 184 is a sheet 185 of rubber, or likeyieldable material, which is the element of the liner 180 that actuallyforms the mulling surface inside the receptacle 45. The metal backingplate 184 of the liner section 181 is the element by which the linersection 181 is secured to the receptacle shell 48. For this purpose, therubber sheet 185 is set back from each end of the metal backing plate184 to expose the latter along a narrow strip. Curved metal bars 186,187are placed against the metal backing plate 184 at the end walls 49,511,respectively, for the purpose of securing the liner 180 to thereceptacle shell 48. Each of the curved bars 186,187 is of the samearcuate length and the same thickness as the rubber sheet 185, so thatthe curved bars 186,187 are coextensive and flush therewith. Each curvedbar 186,187 has several flush bolts 188 which extend through the curvedbars 186,187, the metal backing plate 184 and the receptacle shell 48,and project beyond the latter for the reception of suitable nuts bywhich the curved bars 186,187, are firmly secured to the receptacleshell 48 and thereby secure the liner section 181 in place as described.

As best seen in FIG. 6, each of the liner sections 181,182 extendsthrough one-half the arcuate length of the receptacle shell 48, notincluding the arcuate length of the cover 55. The liner sections 181,182abut each other to form the liner 180 extending continuously around thefixed portion of the receptacle shell 48. The liner section 183 iscoextensive with the arcuate extent of the cover 55, and when the latteris in closed position, the ends of the liner section 183 abut theexposed ends of the liner sections 181,182, whereby the liner 188extends through the full inner circumference of the receptacle shell 48,and the rubber sheet 185 thereof provides an endless mulling surfacethat faces inwardly of the receptacleshell 48 and is disposed around theaxis of the shaft 85. As seen in FIG. 5, the liner section 181 is cutaway at the discharge section 102 to provide an opening connecting tothe discharge chute 38.

Each mulling assembly a-h is operative to mull the sand in thereceptacle 45. The mulling, as such, is accomplished by the severalmulling wheels of the mulling assemblies 105ah and the liner 180. Themulling action, comprising the pressing, kneading and mixing of thesand, takes place between the mulling wheels 135 and the liner 180. Thesand is dispersed on the liner about the axis of the shaft 85, and themulling wheels 135 engage the sand that is so dispersed on the liner180, and there is a pressing, kneading and mixing action of the mullingwheels 135 on the sand to accomplish the mulling of the sand. The sandas it flows longitudinally through the receptacle 45, and is dispersedtherein, is highly abrasive in its action, on the elements of theapparatus, and particularly so in respect to the elements which areoperative to work the sand. Thus, each mulling wheel 135 is providedwith the tire 153 made of yieldable material, and likewise, the liner180 includes the sheet of yieldable material to form the mullingsurface, which are more resistant to the wearing, abrasive action of thesand than would be the case with nonyieldable materials, for example,metal. The operation of the continuous muller 20 will be described ingreater detail hereinafter.

The construction of the mulling assembly 1115b is typical of each of themulling assemblies l05ah, each of which includes all the elements whichhave been described. The mulling assembly 105a includes an additionalelement which is the intake accelerating plow 190, as best seen in FIGS.6 and 10. A bar 191 is secured to the first mounting arm 111 of theframe 107 in a suitable manner, as by welding. The plow has an arm 192extending upwardly to meet the lower end of the bar 191 and isreleasably secured to the latter by a pair of bolts 193. The bolts 193may be released for the purpose of replacing the intake acceleratingplow 190 if it should experience excessive wear. The plow 190 has a plowblade 194 which is disposed substantially parallel to the axis of theshaft I ll 85, and is in front of the mulling wheel 135 to lead thelatter in the direction of movement thereof around the axis of the shaft85, this being in a clockwise direction, as viewed in FIG. 6. The intakeaccelerating plow 190 meets the sand as it initially flows into thereceptacle 45, and gives such sand an initial acceleration or movement,and in effect disperses the sand to prevent it from piling upexcessively in front of the mulling wheel 135 of the first mullingassembly 105a. By reason of the gap between the plow blade 194 and theliner 180, a substantial amount of sand remains ahead of the mullingwheel 135 to be acted upon thereby. Other than as stated with respect tothe mulling assembly 105a, the several mulling assemblies 105ah arealike in construction.

At the discharge section 102 of the receptacle 45 there is provided aradially extending sweeper blade 195, as best 27 seen in FIGS. and 11.Near the end wall 50, a partial hub 196 is secured to the shaft 85, asby welding. The partial hub 196 has the same configuration as theseveral partial hubs 106 for the mulling assemblies 105a-h. The sweeperblade 195 has a hub portion 197 that is placed on the shaft 85 adjacentthe partial hub 196, and the sweeper blade 195 is secured to the partialhub 196 by a plurality of bolts 198, which may be three in number. Thesweeper blade 195 is formed as a planar element disposed in a plane thatis placed laterally with respect to the shaft 85. The sweeper blade 195rotates with the shaft 85 in front of the end wall 50. As the sand flowsdownstream and reaches the discharge section 102 it would normally havea tendency to adhere to the end wall 50 and to accumulate on the same.However, the rotating sweeper blade 195 prevents such accumulation ofthe sand, and accordingly, the sand continuously discharges through thedischarge chute 38 at the same rate as the rate of movement of the sandinto and through the receptacle 45.

The operation of the mulling apparatus 20 will now be described. Thesand flows into the receptacle 45 from the feed chute 27 and through thefeed opening 100 at the feed or upstream end thereof. As the sand entersthe receptacle 45, it is met by the intake accelerating plow 190 whichstarts the sand in movement around the axis of the shaft 85 and preventsan excessive accumulation of sand in front of the mulling wheel 135 ofthe mulling assembly 105a. The intake accelerating plow 190 impels thesand in a lateral direction with respect to the axis of the shaft 85.However, the sand also has a tendency to fan out upstream and downstreamfrom the opposite side edges of the plow 190. On the upstream side thesand is blocked by the end wall 49, and on the downstream side the sandis blocked by the dam 155. Accordingly, the movement of the sandimpelled by the accelerating plow 190 is essentially in a lateraldirection with no significant upstream or downstream movement.

The mulling wheel 135 of the mulling assembly 105a follows closelybehind the intake accelerating plow 190, the mulling assembly 105a beingmoved in a clockwise direction by the shaft 85 about the axis of thelatter, as viewed in FIG. 6. The dam 155 extends to almost the axis ofthe mulling wheel 135. Behind the dam 155 and ahead of the mulling wheel135 there is retained sand that is engaged by the mulling wheel 135.Thus, the association of the intake accelerating plow 190 with the dam155 and the end wall 49 assures that while excessive accumulations ofsand are removed from the path of the mulling wheel 135, nevertheless asubstantial amount of sand remains in the path of the mulling wheel 135to be engaged by the latter and to be pressed, kneaded and mixed therebyon the mulling surface of the liner 180.

The shaft 85 is rotated at a relatively high rate of speed, sufficientto cause the mulling wheel 135 to be moved outwardly towards the mullingsurface of the liner 180 by centrifugal force. The limit of the outwardmovement of the mulling wheel 135 in response to the action ofcentrifugal force is determined by the upper arm 126 and the setting ofthe eccentric disc 163. The mulling action is found to be most effectivewhen there is provided a gap between the periphery of the mulling wheel135 and the mulling surface of the liner 180, for

example as seen in FIGS. 6'and 7. The maintenance of such a gap preventsthe grains of sand from being crushed, which would otherwise occur, andthe action of the mulling wheel 135 on the sand is then, in true effect,only a pressing, kneading and mixing action, which is the requisiteaction for properly combining-the sand with the bonding ingredients. Theoptimum gap between the periphery of the mulling wheel 135 and themulling surface of the liner 180 may be different for different sands,different combinations of sand and bonding ingredients, and differentoperating conditions. Accordingly, the eccentric disc 163 may be set toprovide the appropriate gap between the mulling wheel 135 and themulling surface of the liner 180. The eccentric disc 163 also providesan adjustment for wear of the mulling wheel tire 153. As such tire 153wears down, the gap increases and by resetting the eccentric disc 163the gap may be closed and restored to its proper dimension.

As the mulling wheel 135 moves around the axis of the shaft and over themulling surface of the liner 180 to press, knead and mix the sand, italso packs the sand against the mulling surface. Such packed sand isremoved from the mulling surface of the liner 180 by the plow 170 thatfollows behind the mulling wheel 135 in the direction of movement of themulling assembly a around the axis of the shaft 85. The plow blade 175has its leading edge disposed closely adjacent to the mulling surface ofthe liner 180, with sufficient clearance being provided to prevent theplow blade 175 from damaging the liner 180. The plow blade 175 engagesthe sand that is packed on the mulling surface, to remove such sandtherefrom by a scraping action. By reason of the speed of the plow 170over the mulling surface of the liner 180, and the selected angle of theplow blade 175 with a tangent to the mulling surface, the engagement ofthe plow blade 175 with the sand causes the latter to be impelled in alateral direction with respect to the axis of the shaft 85, and aboutthe axis of the shaft 85 over the mulling surface, whereby such sand isbroken up and is dispersed in the receptacle 45. The sand fans out in anupstream and a downstream direction from the plow blade 175, as anincident to being impelled in a lateral direction. In order not toimpede or interfere with the impulsion and dispersion of the sand by theplow blade 175, the plow 170 is spaced a sufficient distance behind themulling wheel such that the sand effectively clears the mulling wheel135 as it is impelled and dispersed by the plow 170.

It is a concomitant of the impelling action of the plow on the sand thatthe sand is distributed around the circumference of the receptacle 45and is substantially uniformly distributed over the mulling surface ofthe liner 180 throughout the circumference of the latter. Thus, the sandis mulled on the mulling surface of the liner 180 between it and themulling wheels 135 throughout the circumference of the cylindricalmulling surface.

As the sand is impelled laterally, it fans out from the plow blade inupstream and downstream directions. However, the sand which fans outfrom the plow blade 175 in an upstream direction meets greaterresistance to such movement than does the sand which fans out in adownstream direction, by reason of the fact that additional sand iscontinuously being delivered at the upstream end of the receptacle 45,while sand is continuously discharging from the discharge section 102 atthe downstream end of the receptacle 45. Thus, there is a pressure headcondition in the receptacle 45, whereby the sand flows in a streamthrough the receptacle 45 in a longitudinal direction from the feed orupstream end to the discharge or downstream end thereof, rather thanbeing positively fed through the receptacle 45. In this manner, a givenportion of sand flows longitudinally to the successive mulling positionsah along the length ofthe muller receptacle 45, to be successivelymulled by the respective mulling assemblies 105a-h. The plows 170 do notact in any manner to positively feed the sand in a longitudinaldirection as do plows that are sharply angled or inclined with respectto the longitudinal axis. The plows 170 are operative to put the sand inmotion and to each mulling assembly 105 trails, or is disposed behindthe preceding mulling assembly 105 in the direction of rotation thereofabout the axis of the shaft 85. In the preferred embodiment of theinvention disclosed herein, the angle between one mulling assembly 105and a successive mulling assembly 105 is less than 180, so that whenviewed along the shaft 85 the successive mulling assemblies 105ah havethe appearance of being disposed along a helix.

The relative angular disposition of one mulling assembly with respect tothe preceding mulling assembly is best illustrated in FIG. 6, whereinthe mulling assembly 105a is illustrated in solid lines, and certainelements of mulling assembly l05b are illustrated in phantom lines; thelatter are identified as the mulling wheel 135b, the dam 155b and theplow 170b. The plow blade 175 of the mulling assembly 105a is disposedsomewhat in alignment in a longitudinal direction with the leading edgeof the dam l55b. The mulling wheel 135b follows behind the dam 155b,although it overlaps the dam 155b, and the plow 17% is spaced a distancebehind the mulling wheel 135 to follow the latter. As the plow blade 175of the mulling assembly 105a scrapes the sand from the mulling surfaceand disperses the sand about the axis of the shaft 85, the sand flowsdownstream. However, the dam l55b of the successive mulling assembly105b, to some extent, overlaps the plow blade 175, and although spaceddownstream therefrom, in effect, it follows the plow blade 175. Thus, asthe sand flows downstream by reason of being put in motion and dispersedover the mulling surface about the axis of the shaft 85, the

dam 'l55b is interposed in the line of flow of the sand to momentarilyinterrupt such flow, whereby the dam 1551; causes a mass of sand toaccumulate in front of the mulling wheel 13512. As the mulling wheel135b follows the darn 155b in the clockwise movement thereof, it worksits way through the mass of sand that is momentarily accumulated behindthe dam 155b and in front of the mulling wheel 135b. Thus, in effect,the dam 155b functions to collect .the sand to be worked by the mullingwheel 135b. The working or mulling of the'sand is enhanced by the factthat there is the accumulation of sand behind the dam 155b, in thatthere is an augmented movement of the sand particles relatively to eachother, which improves the pressing, kneading and mixing action on thesand by which it is combined with the bonding ingredients, and to coatthe sand particles with such bonding ingredients.

- -As the mulling wheel 135 moves around the axis of the shaft 85, eachmulling wheel 135 also rotates about its own axis. The mulling wheels135 do not rotate on the mulling surface of the receptacle liner 180.Rather, the mulling wheels 135 engage the sand on the mulling surface ofthe liner 100 and rotate relatively to the mulling surface. At alltimes, the mulling wheels 135 are thrust outwardly by the centrifugalforce acting on the same, so that the mulling wheels 135 effectivelypress the sand between the peripheries of the mulling Wheels 135 and themulling surface of the receptacle liner 180; As the mulling wheels 135thus work their way through the'sand that is dispersed on the mullingsurface, all the while rotating about their own axes, the mulling wheels135 are effectively pressing, kneading and mixing the particles of thesand, whereby there is ultimately produced a complete homogeneouscombination of the sand with the bonding ingredients, in which theindividual grains of the sand are coated with the bonding ingredients.

There is a gap between the arcuate outer edge 162 of the dam 155 and themulling surface of the liner 180. This gap can be adjusted by means ofthe slots 158,159 and the bolts 160,161. An increased gap will have the"effect of permitting more sand to flow downstream throughthe gap andpast the clam, while narrowing the gap has the opposite effect. Theulti' mate effect of such adjustment is to adjust the retention time ofthe sand in the receptacle45, which in turn affects the quality of themulling action. Adjustment of the position of the dam 155 is alsorequired in ordei' that it-rr ay be properly positioned in accordancewith the selective positioning of the mulling wheel relatively tothemullirig' surface, by means of the eccentric disc 163, as previouslydescribed.

The plow 170b follows at a distance behind the mulling wheel 135k and itscrapes the mulled sand from the mulling surface and disperses the sandover the mulling surface and about the axis of the shaft 85, as has beendescribed. The operation, as described with respect to the mullingassemblies 105a, 105b, repeats itself downstream as to the successivemulling assemblies 105ah. The total effect of the operation is that thesand continuously flows through the muller receptacle 45 towards thedischarge section 102; however, such flow is momentarily interrupted asthe respective dams move about the axis of the shaft 85. Suchinterruptions of the downstream flow of the sand merely restrain thecontinuous flow of a portion of the sand in order to enhance the mullingof the same. The effect of the operation of the dams 155 is to reducethe effective or overall rate of flow of the stream of sand through thereceptacle 45, so that the retention time of the sand in the receptacle45 is sufficient for effective mulling of the sand, as well as toproduce an accumulation of sand in front of the mulling wheels 135 foreffective mulling action.

It is believed that during the operation of' the mulling apparatus 20the sand is distributed on the mulling surface of the liner 180 in acylinder from the upstream end to the discharge section 102 at thedownstream end of the receptacle 45. It appears that such cylinderdiverges internally towards the discharge section 102, so that, ineffect, there is a downhill condition in the receptacle- 45. Since thesand is always maintained in a dynamic condition of movement in thereceptacle 45 by the action of the plows dispersing the sand over themulling surface, the sand readily flows downstream under the force ofthe pressure head that exists by reason of the sand being continuouslyfed in at the upstream end of the receptacle 45 and discharged at thedischarge section 102.

The torsion bushings 114 provide a flexible or yieldable connectionbetween the shaft 118 and the sleeve 113. The rubber cylinders 116 ofthe torsion bushings 114 have a neutral position and any distortionthereof from the neutral position gives rise to force which opposes suchdistortion. This force may be characterized as the spring rate of theyieldable cylinders 116. The interposition of the torsion bushings 114between the sleeve 113 and the shaft 113 produces a smoother operationof the mulling wheels 135 under the action of centrifugal force, in thatthe wheels 135 are not subjected to sudden and erratic thrusting thereofin response to the action of centrifugal force, or upon encounteringuneven accumulations of sand on the mulling surface.

It has been found desirable to place the torsion bushings with theneutral position of the yieldable cylinders 116 located in suchposition, that the mulling wheels 135 in the idleposition of theapparatus are placed at a position intermediate the periphery of theshaft 85 and the mulling surface of the liner 180. When the apparatus isin operation, the relatively high speed of rotation of the shaft 85gives rise to a centrifugal force that thrusts the mulling wheels 135 totheir maximum outer position, as determined by the selected position ofthe eccentric disc 163. In moving to such position, the yieldablecylinders 116 of the torsion bushings 1 14 are distorted by reason ofthe metal sleeves 115 turning relatively to the fixed sleeves 113 on thefirst mounting arms 111. The distortion of the torsion bushings 114 isgreatest at the maximum outer position of the mulling wheels 135, andaccordingly, the resisting force of the torsion bushings is greatest atthis position of the mulling wheels 135. The resisting force of thetorsion bushings 114 acts in the opposite direction from the centrifugalforce on the mulling wheels 135, and the effect is to reduce thecentrifugal force. However, if for any reason the mulling wheels 135move inwardly, then the resisting force of the torsion bushings 114 isreduced, and the negative effect thereof on the centrifugal force islikewise reduced. The overall effect is a degree of compensation by thetorsion bushings 114 for the loss of centrifugal force that occurs byreason of the mulling wheels 135 moving inwardly from their outermostpositions. The torsion bushings 114 may be selected to provide suchmagnitude of resisting force and cushioning effect as may be desired fora given construction of the continuous muller 20.

The mulling apparatus 20 which is described herein provides a means forpracticing a novel method of mulling material, such as sand. In suchmethod, the sand is continuously delivered to and discharged from thereceptacle within which the mulling is performed. The sand is dispersedin the receptacle and is distributed on a cylindrical mulling surface,whereby the sand continuously flows in a stream through the receptacle.The sand that is distributed on the mulling surface is mulled on suchmulling surface. The mulling takes place concurrently with the flow ofthe stream of sand through the receptacle. The total effect of theseveral steps is a process for continuously mulling sand such that sandmay be continuously delivered and fed into the receptacle to be mulled,and likewise, the sand is continuously discharged from the receptacleafter such mulling operation.

The improved continuous mulling apparatus described herein provides ameans whereby the material flows continuously in a stream through theapparatus. Such flow is interrupted or restrained from time to time foraccumulating a quantity of material to be mulled. However, there is nodisturbance of the overall continuous flowing condition of the materialfrom the upstream end of the apparatus to the downstream end of theapparatus. In accordance with the invention, the material is dispersedabout the axis of the mulling apparatus in a lateral direction todistribute the material on the mulling surface, and is maintained in adynamic condition for the downstream flow of the material through theapparatus, which is required for continuous operation. It is an inherentfeature of the mulling operation disclosed herein that the material isvery effectively aerated by reason of its dispersion in the apparatus,which causes the material to be broken up so that when ultimatelydischarged it is in true granular fonn.

Obviously those skilled in the art may make various changes in thedetails and arrangement of parts without departing from the spirit andscope of the invention as defined by the claims hereto appended, andapplicant therefore wishes not to be restricted to the preciseconstruction herein disclosed.

lclaim:

l. The method of continuously mulling material comprising the steps,continuously feeding material into a substantially level receptaclehaving an inwardly facing cylindrical mulling surface disposed around alaterally extending axis, dispersing the material around the axis anddistributing the material annularly over the cylindrical mulling surfaceto produce a continuously flowing condition of the material in alongitudinal direction through the receptacle, pressing, kneading andmixing the material on the cylindrical mulling surface to mix andcombine the material with added ingredients, and continuouslydischarging mulled material from the receptacle.

2. The method of continuously mulling material comprising the steps,continuously feeding material and added ingredients into a substantiallylevel receptacle having an inwardly facing cylindrical mulling surfacedisposed around a laterally extending axis, dispersing the material andadded ingredients around the axis and distributing the material andadded ingredients annularly over the cylindrical mulling surface toproduce a continuously flowing condition of the material and addedingredients in a longitudinal direction through the receptacle,

pressing, kneading and mixing the material and added ingredients on thecylindrical mulling surface to mix and combine the material with theadded ingredients, and continuously discharging mulled material from thereceptacle.

3. The method of continuously mulling material comprising the steps,continuously feeding material into a substantially level receptaclehaving a inwardly facing cylindrical mulling surface disposed around alaterally extending axis, impelling the material in a directionlaterally of the axis to disperse the material around the axis and todistribute the material annularly over the cylindrical mulling surfaceto produce a continuously flowing condition of the material in alongitudinal direction through the receptacle, pressing, kneading andmixing the material on the cylindrical mulling surface and continuouslydischarging mulled material from the receptacle.

4. The method of continuously mulling material comprising the steps,continuously feeding material into a substantially level receptaclehaving an inwardly facing cylindrical mulling surface disposed around alaterally extending axis, dispersing the material around the axis anddistributing the material annularly over the cylindrical mulling surfaceto produce a continuously flowing condition of the material in alongitudinal direction through the receptacle, pressing, kneading andmixing the material on the cylindrical mulling surface, said step ofdispersing and distributing the material following the step of pressing,kneading and mixing the material thereby to scrape compacted materialfrom the mulling surface, and continuously discharging mulled materialfrom the receptacle.

5. The method of continuously mulling material comprising the steps,continuously feeding material into a substantially level receptaclehaving an inwardly facing cylindrical mulling surface disposed around alaterally extending axis, dispersing the material around the axis of thecylindrical mulling surface and distributing the material annularly overthe cylindrical vmulling surface to produce a continuously flowingcondition of the material in a longitudinal direction through thereceptacle, pressing, kneading and mixing the material on thecylindrical mulling surface, successive steps of pressing, kneading andmixing the material is aforesaid, successive steps of dispersing anddistributing the material as aforesaid, and continuously dischargingmulled material from the receptacle.

1. The method of continuously mulling material comprising the steps,continuously feeding material into a substantially level receptaclehaving an inwardly facing cylindrical mulling surface disposed around alaterally extending axis, dispersing the material around the axis anddistributing the material annularly over the cylindrical mulling surfaceto produce a continuously flowing condition of the material in alongitudinal direction through the receptacle, pressing, kneading andmixing the material on the cylindrical mulling surface to mix andcombine the material with added ingredients, and continuouslydischarging mulled material from the receptacle.
 2. The method ofcontinuously mulling material comprising the steps, continuously feedingmaterial and added ingredients into a substantially level receptaclehaving an inwardly facing cylindrical mulling surface disposed around alaterally extending axis, dispersing the material and added ingredientsaround the axis and distributing the material and added ingredientsannularly over the cylindrical mulling surface to produce a continuouslyflowing condition of the material and added ingredients in alongitudinal direction through the receptacle, pressing, kneading andmixing the material and added ingredients on the cylindrical mullingsurface to mix and combine the material with the added ingredients, andcontinuously discharging mulled material from the receptacle.
 3. Themethod of continuously mulling material comprising the steps,continuously feeding material into a substantially level receptaclehaving a inwardly facing cylindrical mulling surface disposed around alaterally extending axis, impelling the material in a directionlaterally of the axis to disperse the material around the axis and todistribute the material annularly over the cylindrical mulling surfaceto produce a continuously flowing condition of the material in alongitudinal direction through the receptacle, pressing, kneading andmixing the material on the cylindrical mulling surface and continuouslydischarging mulled material from the receptacle.
 4. The method ofcontinuously mulling material comprising the steps, continuously feedingmaterial into a substantially level receptacle having an inwardly facingcylindrical mulling surface disposed around a laterally extending axis,dispersing the material around the axis and distributing the materialannularly over the cylindrical mulling surface to produce a continuouslyflowing condition of the material in a longitudinal direction throughthe receptacle, pressing, kneading and mixIng the material on thecylindrical mulling surface, said step of dispersing and distributingthe material following the step of pressing, kneading and mixing thematerial thereby to scrape compacted material from the mulling surface,and continuously discharging mulled material from the receptacle.
 5. Themethod of continuously mulling material comprising the steps,continuously feeding material into a substantially level receptaclehaving an inwardly facing cylindrical mulling surface disposed around alaterally extending axis, dispersing the material around the axis of thecylindrical mulling surface and distributing the material annularly overthe cylindrical mulling surface to produce a continuously flowingcondition of the material in a longitudinal direction through thereceptacle, pressing, kneading and mixing the material on thecylindrical mulling surface, successive steps of pressing, kneading andmixing the material is aforesaid, successive steps of dispersing anddistributing the material as aforesaid, and continuously dischargingmulled material from the receptacle.